1. Field of the Invention
The present invention relates to a positioning system and method for a precise stage and more particularly to a positioning system and method for a precise stage by means of electron beam scanning.
2. Description of the Prior Art
With requirements of high precision for industrial machinery and measuring instruments, development of precision machinery, semiconductor industry, micron technology or nanotechnology all emphasize on micronization and precision, wherein positioning technique and instruments with high precision are necessary for processing machinery, semiconductor fabrication and electronic information device.
Generally, when a high precision stage is rotating or multi-axis positioning, it may lead to a problem of mechanical drift. The state-of-art solutions and disadvantages thereof are described below:                (1) Using an optical interferometer to detect precision movement of the moving stage for high precision positioning: it cannot be arranged on the rotating axis of the moving stage.        (2) Using an optical scale for calibration: precision thereof is insufficient and it is unable to measure eccentricity of the rotation.        (3) Using a mechanical axis with air bearing: although to 30 nm precision, it must be operated under standard atmosphere and is too large-sized to use in small space.        (4) Using a vacuum gauge for calibration: if the stage is designed for multi-dimensional movement with tilted angle, the mechanical design is very difficult and complex and therefore is unpractical.        